1. Field of the Invention
The present invention relates to a liquid crystal display device and more particularly, to a liquid crystal display device capable of reducing display deficiencies due to electric noise (noise) and of obtaining clearer images.
2. Discussion of Background
A conventional liquid crystal display device is known to comprise, as shown in FIG. 10, a liquid crystal panel 1 having a printed board for a liquid crystal driving circuit 2, a lamp 3, a lamp reflector 4, a lamp cover (rear reinforcement) 11, a plurality of optical sheets 5, a light-conducting plate 6, a reflecting sheet 7, a mechanism part including a resinous frame 8, a rear frame 10 for supporting and fixing the lamp cover 11 and the reflecting sheet 7, and a front frame 9 for fixing these.
Accompanying demands for small-sized frames, display deficiencies due to electric noise are generally considered to be problematic in such a conventional liquid crystal display device provided with a conductive lamp reflector, and in order to avoid such deficiencies, it is necessary to connect the lamp reflector to GND (to ground the same). A general method for grounding the lamp reflector is a method wherein the lamp reflector is made to electrically contact ground or GND through the lamp cover 11, rear frame 10, or front frame 9, which are frame bodies of metal.
Various other methods include: a method in which, at the time of fixing the entire liquid crystal display device through calking of the front frame which is a metallic frame body, grounding is performed by making a calking piece simultaneously contact the lamp reflector; a method in which grounding is performed by providing conductivity between the lamp reflector and the front frame, which is a metallic frame body, by means of an electric conductive tape, such as a copper tape; a method in which grounding is performed by making a protrusion or an extension, formed on the metallic frame body, contact the lamp reflector; or a method in which grounding is performed by providing conductivity between the lamp reflector and the metallic frame body by means of soldering.
However, in a conventional liquid crystal display device employing a grounding method wherein contact is performed using a calking piece or protrusion/extension, a drawback is presented that grounding cannot be reliably performed since contact deficiencies might occur between the metallic frame body and the lamp reflector when shock is applied to the liquid crystal display device. Further, in a liquid crystal display device employing a method using an electric conductive tape or soldering, a drawback is presented that assembly of the liquid crystal display device becomes more costly.
In view of the above-stated facts, it is an object of the present invention to provide a liquid crystal display device capable of reducing display deficiencies due to electric noise and capable of obtaining clearer images.
The liquid crystal display device, according to a first aspect of the present invention, comprises: a transmission-type liquid crystal panel; a sheet-like light source device for radiating light to a back surface of the liquid crystal panel, the sheet-like source device including a lamp, a conductive lamp reflector, and a light-conducting plate; a circuit board connected to the liquid crystal panel for supplying a signal necessary for driving the liquid crystal panel; and a mechanism part for housing a holding all three of the liquid crystal panel, the sheet-like light source device, and the circuit board, wherein the mechanism part includes at least one metal part, and wherein the at least one metal part is fixedly attached to the lamp reflector via screw fastening means.
It is preferable that the metal part to be connected to the lamp reflector forms at least a part of a display surface side and a part of a side of the liquid crystal display device.
It is preferable that the metal part to be connected to the lamp reflector forms at least a part of a back surface of the liquid crystal display device.
It is preferable that the metal part to be connected to the lamp reflector forms at least a part of a back surface and a part of a side of the liquid crystal display device.
It is preferable that the metal part to be connected to the lamp reflector is so arranged to cover the lamp reflector.
It is preferable that the screw fastening means is composed of a screw and a female screw working, or a screw and a calking nut.
It is preferable that, at a fixation portion through the screw fastening means, the metal part is fixedly attached to the lamp reflector together with at least one other component.
The liquid crystal display device, according to a second aspect of the present invention, comprises: a transmission-type liquid crystal panel; a sheet-like light source device for radiating light to a back surface of the liquid crystal panel, the sheet-like source device including a lamp, a conductive lamp reflector, and a light-conducting plate; a circuit board connected to the liquid crystal panel for supplying a signal necessary for driving the liquid crystal panel; and a mechanism part for housing and holding all three of the liquid crystal panel, the sheet-like light source device, and the circuit board, wherein the mechanism part includes at least one metal part, and wherein the at least one metal part is fixedly attached to the lamp reflector via a pinch fastening means obtained by plastic working.
It is preferable that the pinch fastening means is obtained by inserting either one of a protruding or an extending piece or a protruding or an extending cylindrical body protruding or extending from either the lamp reflector or the at least one metal part into a hole through either one of the lamp reflector or the at least one metal part, respectively and then, crushing either one of the protruding or extending piece or the protruding or extending cylindrical body.
It is preferable that, at a fixation portion through the pinch fastening means obtained by plastic working, the at least one metal part is fixedly attached to the lamp reflector together with at least one other component, such as a lamp cover.
The liquid crystal display device, according to a third aspect of the present invention, comprises: a transmission-type liquid crystal panel; a sheet-like light source device for radiating light to a back surface of the liquid crystal panel, the sheet-like source device including a lamp, a conductive lamp reflector, and a light-conducting plate; a circuit board connected to the liquid crystal panel for supplying a signal necessary for driving the liquid crystal panel; and a mechanism part for housing and holding all three of the liquid crystal panel, the sheet-like light source device, and the circuit board, wherein the mechanism part includes at least one metal part, and wherein the at least one metal part is fixedly attached to the lamp reflector via a snap pressing means for achieving fixed attachment in a freely attachable/detachable manner.
It is preferable that the snap pressing means is a pin member having a head and a shank extending outwardly from the body, wherein the shank includes a slit and wherein the shank extends through a hole in a longitudinal direction.
It is preferable that, at a fixation portion through the snap pressing means, the at least one metal part is fixedly attached to the lamp reflector together with at least one other component, such as a lamp cover.
It is preferable that the snap pressing means is a pin member having a slit which pierces through in a longitudinal direction.
It is preferable that, at a fixation portion through the snap pressing means, the metal part is fixedly attached to the lamp reflector together with at least one other component.